Method and device for separating samples from a liquid

System, method, and computer program product for synchronizing a system for aspirating and/or dispensing of liquid samples that includes a microejection device and a pump, which are connected with one another via tubing, wherein a computer is capable of being loaded with an activatable computer program product for synchronizing operation of the microejection device and the pump. Embodiments are characterized in that the loaded and activated computer program product, directs the computer to control and synchronize the system: (a) to actively define a sample volume and dispense the defined sample volume using the microejection device, which is filled with sample liquid; and (b) to track a part of the pump that conveys liquid around a value, dependent on the sample volume, which is defined and is actively dispensed only by the microejection device, to prevent excessive pressure differences in the microejection device, tubing, and pump.